A celestial-aided navigation system can be utilized to correct for navigation errors, such as drift, in inertial sensors in an inertial navigation system within a vehicle such as, for example, a spacecraft or satellite. One example of a celestial-aided navigation system is a star tracker system. A star tracker system includes an optical device that can be utilized, for example, to determine a vehicle's location, velocity and/or attitude based upon the position of at least one celestial body (e.g., star, planet, the Moon, the Sun), and also determine a two-dimensional reference frame that indicates the position of the celestial body (e.g., in polar or Cartesian coordinates).
It is desirable for a star tracker system to have a field of regard (FOR) as wide as possible and a field of view (FOV) as narrow as possible, in order to be able to detect as much of the sky as possible, and ensure that identifiable celestial bodies can be differentiated between and thus detected by the system involved. For example, it is desirable for a star tracker system to have a cone-shaped FOR with a diameter as wide as 120 degrees, and the ability to measure differential angles between celestial bodies with an uncertainty of less than 1 μrad (1E-6 radians) within a 120 degree maximum FOV (MFOV). However, conventional celestial-aided navigation and star tracker systems nearly capable of measuring such small differential angles, within such large MFOVs, have to utilize very large detector arrays that can differentiate between celestial bodies and detect an image of a celestial body of interest. Notably, such large detector arrays are very costly in terms of their inefficient utilization of limited space, their large power losses, and their high financial costs for procurement and maintenance. Consequently, a need exists for a celestial-aided navigation or star tracker system with a less costly optical image detector array, which can differentiate between celestial bodies within a large MFOV, detect an optical image of a celestial body of interest, and also strive to minimize the size, weight and power (e.g., SWaP) required for the system involved.